limonoid plays anti-inflammatory role by regulating NF-B signaling pathway in lipopolysaccharide-induced macrophages.

BACKGROUND

a well-known tropical tree native to southeastern China, has anti-inflammatory and antioxidant activities, and contains large amounts of limonoids and triterpenoids.

OBJECTIVE

The aim of this study was to investigate the potential anti-inflammatory activity of limonoids from on lipopolysaccharide (LPS)-mediated RAW264.7 cells.

METHODS AND RESULTS

Using a bioassay-guided approach, the chemical fraction with high anti-inflammatory activity was found and its chemical constituents were investigated. Phytochemical studies on active extracts resulted in the separation of three novel phragmalin limonoids (-), together with two known limonoids (-) and 11 tirucallane triterpenes (-). The activity of these isolated compounds in the production of nitric oxide (NO) on LPS-reated macrophages was evaluated. Limonoid indicated significant anti-inflammatory activities with IC value of 4.58 M. Limonoid notably inhibited the production of NO, interleukin- 6 and tumor necrosis factor- on macrophage. Signal transduction and activation of STAT and NF-B activators were effectively blocked by limonoid .

CONCLUSIONS

These results indicate that limonoid has an anti-inflammatory effect by the inhibiting JAK2/STAT3, iNOS/eNOS, and NF-B signaling pathways and regulating inflammatory mediators.